Field of the Invention
The present invention relates to a technique of tracking a person in an image, and more particularly, to an image recognition system or the like configured to track a moving person by using images taken by a plurality of cameras in terms of a sports scene or in a security camera application, or the like.
Description of the Related Art
Conventionally, a system is known in which a moving image of group sports such as soccer, rugby, or the like is taken, and a plurality of persons are automatically detected and tracked and history of locations is recorded. In this system, there is a possibility that tracking fails in a particular situation in which many players gather in a small area, a player moves out of a screen, or in other various difficult situations. When tracking fails, it is necessary to perform a redetermination of a correspondence in terms of persons by making a comparison between a previous image and a current image or correct the correspondence manually by an operator.
A method of identifying a person in a situation such as that described above is disclosed, for example, in U.S. Pat. No. 8,116,534. In the method disclosed in U.S. Pat. No. 8,116,534, a plurality of cameras are installed in a place such as a corridor, and an image of a person passing through the corridor is taken by each camera from an approximately frontal direction. A face area of the person is detected from each image, and each face image is corrected so as to obtain an approximately frontal face. A feature value is then extracted from each corrected face image. A set of feature values is analyzed using a subspace method to identify the person. In this method, use of a plurality of images makes it possible to achieve better robustness than is achieved by a method using a single camera.